a. Field of the Invention
The present invention pertains to heat sinks and specifically to liquid cooled heat sinks.
b. Description of the Background
Cooling of electronics devices is a critical issue in today""s high performance computers. As processor frequencies increase and the pitch sizes decrease, the heat flux of processor chips increase dramatically. Further, the heat distribution across the surface of a processor chip may vary greatly.
Many different heat sinks and heat dissipation methods have been employed. Convection cooled heat sinks or fan-cooled heat sinks have been used with success in various electronic applications. The sizes and cooling air velocities of the heat sinks have increased significantly to meet power dissipation requirements of faster and faster computers. However, further dramatic improvements in cooling efficiency appear unlikely.
Various liquid cooling apparatuses have been contemplated to address the increased heat dissipation requirements. In general, liquid cooling can be used to collect the heat at a heat source such as a processor chip, and transmit the liquid with a pump to a cooling section such as a remotely located radiator. Other designs include passive thermo-siphons and other liquid-cooled designs. Such systems are much more complex than a simple fan-cooled heat sink and have heretofore not come into commercial practice on a large scale.
It would therefore be advantageous to provide an efficient, simple, low cost heat sink that can handle large heat fluxes from electronic components. It would further be advantageous to provide a heat sink that may be adapted to transfer heat from a specific area to another.
The present invention overcomes the disadvantages and limitations of the prior art by providing a system and method for an active heat sink that mounts to one or more electronic components. The heat sink incorporates a pump that causes a liquid to be propelled across a hot area to heat the liquid, then across a cooler area to transfer heat from the hot area to the cooler area. The heat sink has an integral motor that causes the pump to turn without requiring a shaft to penetrate the liquid cavity. The heat sink may have a temperature monitoring device to turn on and off the pumping system.
The present invention may therefore comprise an active heat sink comprising: a heat transfer fluid; a heat sink body having a circuit for the transmission of the heat transfer fluid, the circuit adapted to flow past a hot zone and past a cool zone, the heat sink body being composed of a non-magnetic material; a cover adapted to encapsulate the heat transfer fluid inside of the circuit; a first pump gear and a second pump gear adapted to be mounted in the heat sink body and further adapted to be mounted inside the circuit to propel the heat transfer fluid about the circuit, at least one of the pump gears having a plurality of magnets disposed about a diameter of the one of the pump gears; a plurality of field coils disposed outside of the circuit and adapted to create a plurality of magnetic fields in the vicinity of the plurality of magnets such that the magnetic fields and the magnets may exert an attractive or a repulsive force; and a controlling circuit adapted to turn on and off the plurality of field coils to create the plurality of magnetic fields in a sequence such that the pump gear is caused to rotate.
The present invention may further comprise a method for cooling an integrated circuit comprising: attaching an active heat sink to the integrated circuit, the active heat sink comprising a heat transfer fluid, a heat sink body having a circuit for the transmission of the heat transfer fluid, the circuit adapted to flow past a hot zone and past a cool zone, the heat sink body being composed of a non-magnetic material, a cover adapted to encapsulate the heat transfer fluid inside of the circuit, a first pump gear and a second pump gear adapted to be mounted in the heat sink body and further adapted to be mounted inside the circuit to propel the heat transfer fluid about the circuit, at least one of the pump gear having a plurality of magnets disposed about a diameter of the pump gear, a plurality of field coils disposed outside of the circuit and adapted to create a plurality of magnetic fields in the vicinity of the plurality of magnets, and a controlling circuit adapted to turn on and off the plurality of field coils; and causing the controller to sequentially turn on and off the field coils such that attractive and repulsive forces are created between the plurality of magnetic fields and the magnets such that the pump gear is caused to rotate and thereby propel the heat transfer fluid about the circuit.
The present invention may further comprise an active heat sink comprising: a heat transfer fluid; a first means for containing the heat transfer fluid such that the heat transfer fluid may flow past a hot zone and past a cool zone, the first means being composed of a non-magnetic material; a second means for pumping the heat transfer fluid within the first means, the second means comprising a plurality of magnets mounted to at least one gear and disposed within the first means and a plurality of coils outside of the first means; and a third means for controlling the coils such that the magnets are caused to rotate the at least one gear and cause the heat transfer fluid to be propelled past the hot zone and the cool zone.
The advantages of the present invention are that heat may be transferred throughout a heat sink for more efficient and effective cooling of the heat sink. The heat transfer fluid is fully encapsulated and contained so that potential leak paths are minimized. Further, a gear pump is caused to move without a rotary seal through the fluid cavity to again minimize any leak paths for the fluid. A controller is provided to start and stop operation of the active portion of the heat sink based on the temperature of the heat sink.